Automated Processes Incorporated (API) may not be a household name or roll off the tongue quite like other manufacturers of the time. But ask any engineer

Automated Processes Incorporated (API) may not be a household name or roll off the tongue quite like other manufacturers of the time. But ask any engineer to name three classic “rock” consoles, and the name API is sure to come up. For a company that began as a dream for its founders in 1968, it went on to pioneer the concept of modular console design, total recall, fader/parameter automation and the 500 series channel EQs — considered by many to be the epitome of boutique console-strip EQ.

Developed in association between Waves and API, the Waves API Collection is a bundle of four precision-modeling processors based on renowned API modules: the 550A 3-band equalizer, the 550B 4-band equalizer, the 560 graphic equalizer and the 2500 stereo compressor. Available as either TDM or native editions, the plug-ins come in both mono and stereo components supporting a maximum of 24-bit/192 kHz resolution natively and 24-bit/96 kHz in TDM.

I tested the collection on a Mac G5 dual-1.8 GHz with 4 GB of RAM running OS 10.4.10, Pro Tools/DAE 7.3.1 and Pro Tools|HD Accel hardware with a 192 I/O acting as the main monitoring and input signal interface. Waves' authorization process is still, sadly, quite an arduous journey. You must have a USB iLok key, and the boxed version doesn't come with one. Rather than sending licenses to your iLok.com account for simple download, Waves uses a long and winding proprietary process of challenge-and-response to authorize your key directly from its support site. This involves more than a dozen steps and careful reading of the tutorial available at www.wavesupport.net.


Modeled on the EQ that defined the API sound, the 550A provides reciprocal EQ in three overlapping ranges, each featuring five frequency centers and as high as 12 dB of boost/cut per band in 2 to 3 dB steps. The HF band is detented at 5, 7, 10, 12.5 and 15 kHz, while the LF centers around 50, 100, 200, 300 and 400 Hz; both ranges are individually selectable as either peaking (bell curve) or shelving, and a bandpass filter can be inserted independently of other settings. As opposed to other boutique EQs such as the Helios Type 69 (which Universal Audio modeled for the UAD-1 card), the 550A's bandpass filter from 50 Hz to 15 kHz allows you to, for example, extract rumble/hum and boost frequencies in the low end at the same time; the Helios forces you to choose between boosting or shelf-filtering.

The 550B ratchets things up by adding an extra overlapping band plus several additional frequencies. This time sporting seven detented centers per band, the HF band adds 2.5 kHz and 20 kHz, while the LF band dips as low as 30 and 40 Hz. They also offer shelf/peak switching. The midrange has been broken up into high mid frequency and low mid frequency, which both have a span of as many as five octaves per band; the same gain range and filter curves of the 550A apply.

Both 550s feature Proportional Q, which automatically widens the filter bandwidth at minimal settings and narrows it at higher settings. In this way, you can really push either plug-in harder than you would most other EQs, and it will consistently deliver a smooth, natural sound — even at the most extreme settings. A +30 dB clip level helps accomplish that.

Deeper crossover boundaries between bands make the 550B powerful at problem solving, while the airy highs and sub-lows act as an aural sweetener just like the original. Punching up a rather flat-sounding kick track “all the way” around 75 Hz and 1 kHz, I discovered the drum's true character without destroying the luscious pillowy effect or overhyping the beater click. Despite their powerful boosting capabilities, the 550A and 550B are naturally flat and sound musical; what you hear going in is what you hear coming out — uncolored and true to the source. The intuitive Q adjustment works wonders on everything from snare and toms to bass and electric guitar, allowing you to precisely target a frequency region with the gain maxed and scale back (automatically widening the peak) to taste.

Mono operation of either 550 model proved fairly efficient with inaudible amounts of latency being added to the channel strip at 44.1 kHz and nearly 24 plug-in instances generating only a small spike in processor usage. Because their true stereo operation keeps the channels separate, the plug-ins naturally consume roughly twice the resources in stereo. Actual chip consumption on TDM systems isn't specified by Waves, but surprisingly, I could get only two instances of the stereo 550B per Accel chip; the rest of the collection performed with similar results. I also think the knobs and their silk-screened values are closely spaced. As one example, sometimes when I'd go to click on 12.5 kHz, the level knob of the band located just a few pixels below would jump to zero. I suggest in revisions that Waves space the knobs away from each other or decrease their size 10 percent without affecting the overall footprint of the GUI.


Featuring the same extended headroom of the EQs, the API 560 is a 10-band graphic equalizer from 31 Hz to 16 kHz with one-octave centers on each band, which make it ideally suited for full-spectrum signal enhancement and room tuning. Again, you get a full 12 dB of boost/cut per band using the unique proportional Q automatic bandwidth control, as well as an EQ bypass button if all you want to add is the analog modeling treatment of API's noise/harmonics.

As with all plug-ins in the bundle, the analog-output section on the right features VU meters scaled in dBfs along with a clip LED, which in the stereo version is positioned between the meters. Similar to what I first saw in the Waves SSL Collection, there is the option of running the API plug-ins in either Analog mode, which adds modeled noise and harmonics from the original API hardware, or Standard mode. The analog harmonics, though subtle on soloed tracks, do lend a favorable “glue” to multiple tracks once mixed. Output gain is selectable ±18 dB, where the Polarity Flip switch inverts phase 180 degrees, and a nearby Trim button allows you to set the output to nominal gain with a single click.

Common now to all Waves plug-ins, the WavesSystem toolbar provides advanced preset management, including the handy dual-loading setup that allows two presets to be loaded at a time and the ability to toggle A/B comparisons between them. Setup files, another cool feature, let you build and save a single file containing all presets for a session.


Early compressors had a “feed-back” design, meaning the leveling circuitry (RMS detector) would act upon a signal once it had already passed through the voltage-controlled gain-reduction amplifiers (VCAs). Later designs got their control voltage before the VCA, so the leveling circuitry knew right away that a gain change was required, invoking an immediate response. Logically, that is known as “feed-forward” compression. Of the two, feed-back is more musical and sweeter, but feed-forward provides greater accuracy over attack and release — ideal for drums and other highly transient signals.

With both compression techniques, the API 2500 is one of the most versatile dynamics processors from the “classic” era. The proprietary Thrust control inserts a highpass filter at the RMS detector input, limiting compression response to lower frequencies while applying additional compression to higher frequencies; that effectively reduces pumping and increases the detector's sensitivity to high-frequency peaks. At its most extreme setting, the low end is gently rolled off by 15 dB while the high end is hyped by the same amount, creating a 30 dB linear slope from 20 Hz to 20 kHz straight through a 1 kHz midpoint. Hard-, Medium- and Soft-Knee modes influence the adjustable threshold.

In stereo operation, the 2500 functions as dual-mono parallel processors or as linked units, with variable linkage between left and right channels ranging from independent operation through to 100-percent link strength. Feed-Forward mode has an external sidechain option, while Link mode has a selection of lowpass, highpass or bandpass filters to adjust the shape of the link-control voltage mixing. That can prevent percussive instruments on one channel from coupling and falsely triggering compression on the other. In the output section, gain can be manually adjusted ±24 dB, or the auto makeup gain option allows you to adjust threshold and ratio settings while maintaining a constant output level.

Reaction time of the attack can be as fast as 0.03 ms (also 0.1, 0.3, 1, 3, 10 and 30 ms), while release features six fixed values (0.05, 0.1, 0.2, 0.5, 1 and 2 sec) and one continuous variable setting from 50 ms to 3 sec. The 2500 totally rocked on drums and percussion with an authoritative sound and enormous headroom for gain reduction without clipping. Combined with the 550 EQs, the 2500 made vocals, bass, acoustic guitar, piano and keys jump through the speakers with only heightened character and no detrimental edginess or tonal skewing. I could bring out the vintage woody snap of a snare or big roomy tom decay without destroying or smearing other neighboring frequency characteristics of their head/shell relationship. The extended highs of the 550B made hats and overhead mics shimmer like high polish.

The bundle is pricey — especially for TDM users — although street prices should be about 25 percent lower. I'd love to see the plugs sold separately; the 550A and 2500 could be huge individual sellers. Regardless, the API Collection can dramatically improve mixes with very little effort or learning curve and give you that big, punchy rock sound that API does so well.


API COLLECTION > $1,000 (NATIVE); $2,000 (TDM)

Pros: Big, punchy API sound. Accurate emulation of the original hardware characteristics, including all the quirks. Large and attractive interface. All major plug-in formats supported.

Cons: Pricey. Authorization process a hassle. Processor-hog in TDM mode.



Mac: G5 or Intel Core Duo/1.8 GHz; 512 MB RAM; OS 10.4.x; RTAS, AudioSuite, Audio Units, VST, MAS or TDM (PowerPC only) host; iLok USB key

PC: P4 2.8 GHz/AMD Athlon 64; 1 GB RAM; Windows XP 32-bit SP2 (Vista not supported yet); RTAS, AudioSuite, VST, DirectX, TDM-compatible host; PACE iLok key